Ruthenium amine

Creutz C and Taube H 1973 Binuclear complexes of ruthenium amines J. Am. Chem. Soc. 95 1086... 

Owing to the presence of the amine and cyanide ligands, known to give rise to specific donor-acceptor interaction with solvents [126-130], an interesting solvatochromic behavior is observed for these species. For complex 1 the spectral changes are dominated by amine interactions with the solvents as shown by the linear correlation of the solvent donor number [131] with the IT band maxima and with the half-wave potential of the ruthenium amine moiety. 

Like ruthenium, amines coordinated to osmium in higher oxidation states such as Os(IV) are readily deprotonated, as in [Os(en) (NHCH2CH2NH2)]2+ [111614-75-6]. This complex is subject to oxidative dehydrogenation to form an imine complex (105). An unusual Os(IV) hydride, [OsH2(en)J2+ [57345-94-5] has been isolated and characterized. The complexes of aromatic heterocyclic amines such as pyridine, bipyridine, phenanthroline, and terpyridine are similar to those of ruthenium. Examples include [Os(bipy )3 ]2+ [23648-06-8], [Os(bipy)2acac] [47691-08-7],... 

Adding N-formyl product (and other amides such as N,N-dimethyl-acetamide) decreases the carbonylation rate, and thus accumulation of product slowly poisons the catalyst. The rate for the piperidine system (Table I) after 70 hrs decreased to 0.4 X 10"5M sec1, and at this stage about 100 moles of amine were carbonylated per mole of ruthenium. Amine solutions of the dimers are quite stable at 75 °C for long periods in vacuo or under argon, and there is no trace of N-formylamine. 

Hamachi I,Takashima H,Tsukiji S, Shinakai S, Nagamune T, Ogoshi H. Electron transfer from Zn-protoporphyrin IX to ruthenium amine attached at His63 of reconstituted cytochrome b562- Chem Lett 1999 551-2. 

Tfouni E, Krieger M, McGarvey BR, Franco DW. Structure, chemical and photochemical reactivity and biological activity of some ruthenium amine nitrosyl complexes. Coord Chem Rev 2003 236 57-69. 

Convergence of spectroscopic and kinetic electron transfer parameters for mixed-valence binuclear dipyridylamide ruthenium amine complexes 05CCR(249)507. 

Outer Coordination Sphere Catalysts. In the classical hydrogenation catalysis shown previously, the substrate must be coordinated to the metal prior to its insertion into a metal-hydrogen bond. However, in recent years, it has been found that unsaturated polar bonds can be hydrogenated without coordination of the substrate to the metal (37). Two well-known, nonclassical possibilities for the hydrogenation of unsaturated polar bonds, such as ketones, are the metal-ligand bifunctional mechanism (38) and the ionic mechanism (39). In the metal-ligand bifunctional mechanism discovered by Noyori (recipient of the Nobel Prize in 2001) for highly efficient ruthenium amine complexes, the hydridic RuH and... 

Density functional theory calculations have led to the proposed mechanism shown in Scheme 12.2. A base-generated ruthenium amido complex activates H2 to afford a ruthenium amine hydride intermediate. In the rate-determining step, transfer of a Ru—H/N—H pair in the outer sphere yields a hemiacetal complex, which degrades via ruthenium-induced C—O cleavage and proton transfer from OH to NH to yield alcohol and aldehyde the latter undergoes outer-sphere reduction to alcohol. 

The diversity of structures is matched by a wide range of mechanisms. While the ruthenium—amines may act by a DNA-binding mechanism the rhodium carboxylates inhibit DNA synthesis but do not bind directly to the doubly stranded polynucleotide. In the latter case a possible mechanism is inhibition of precursor enzymes. Copper thiosemicarbazones and gold diphosphines appear to act by release of the toxic ligand. For thiosemicarbazones the ultimate target is ribonucleotide reductase. Other copper complexes have been developed to mimic the action of superoxide dismutase. 

Metal complexes as antiprotozoal agents are also known, including rhodium, platinum and ruthenium amines. The antiparasitic action of porphyrins is also related to metal sequestration and conversion to the zinc chelate may be the initial step in activation. 

An increase of HDA concentration led to a higher rate of nanoparticle formation from Ru3(CO)i2, while an increase of PA concentration had the opposite effect. This is likely to be related to the presence of ruthenium-amine and ruthenium-carboxylate complexes as intermediates in the synthetic process. Before the formation of the nanostars, quasi-spherical and unbranched nanoparticles were first... 

Privalov and Backvall [25,63] used DFT computations to study the feasibility of an inner-sphere mechanism for reduction of Me2C=NMe by 2. They included solvent in their computations and found two possible rate-limiting steps of similar energy for the inner-sphere mechanism imine coordinatirMi to ruthenium via ring slippage (15 kcal mole ) and hydride transfer to give an (rj -cyclopentadienone) ruthenium amine intermediate (12 kcal mole ). 

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